Sensor Crop Factor Calculator
Solve Sensor Crop Factor step by step — enter coefficients or expressions to get roots, factors, or simplified forms with detailed algebraic working.
Formula
Crop Factor = Full-Frame Diagonal / Sensor Diagonal
The crop factor is calculated by dividing the diagonal of a 35mm full-frame sensor (43.27mm) by the diagonal of the camera sensor. The equivalent focal length equals the actual focal length multiplied by the crop factor. The equivalent aperture for depth-of-field comparison is the actual aperture multiplied by the crop factor.
Worked Examples
Example 1: APS-C with 35mm Lens
Problem: Calculate the equivalent focal length and field of view for a 35mm f/1.4 lens on a Nikon APS-C camera (23.5 x 15.6mm sensor).
Solution: Sensor diagonal = sqrt(23.5^2 + 15.6^2) = sqrt(552.25 + 243.36) = sqrt(795.61) = 28.21mm\nFull-frame diagonal = sqrt(36^2 + 24^2) = 43.27mm\nCrop factor = 43.27 / 28.21 = 1.534\nEquivalent focal length = 35 x 1.534 = 53.7mm\nEquivalent aperture (DoF) = f/1.4 x 1.534 = f/2.15\nHorizontal FoV = 2 x atan(23.5 / 70) = 37.1 degrees
Result: Crop Factor: 1.534x | Equiv. FL: 53.7mm | Equiv. Aperture: f/2.15
Example 2: Micro Four Thirds with 25mm Lens
Problem: What is the full-frame equivalent of a 25mm f/1.8 lens on a Micro Four Thirds sensor (17.3 x 13mm)?
Solution: Sensor diagonal = sqrt(17.3^2 + 13^2) = sqrt(299.29 + 169) = sqrt(468.29) = 21.64mm\nCrop factor = 43.27 / 21.64 = 2.0\nEquivalent focal length = 25 x 2.0 = 50mm\nEquivalent aperture = f/1.8 x 2.0 = f/3.6\nHorizontal FoV = 2 x atan(17.3 / 50) = 19.1 degrees
Result: Crop Factor: 2.0x | Equiv. FL: 50mm | Equiv. Aperture: f/3.6
Frequently Asked Questions
What is sensor crop factor and why does it matter in photography?
Sensor crop factor is the ratio of a full-frame sensor diagonal (43.27mm) to your camera sensor diagonal. It tells you how much narrower your field of view is compared to a 35mm full-frame camera using the same lens. A crop factor of 1.5x means your sensor captures a smaller portion of the image circle projected by the lens, effectively cropping the edges. This matters because it changes the equivalent focal length, apparent depth of field, and effective aperture for noise comparison. A 50mm lens on a 1.5x crop sensor gives the same field of view as a 75mm lens on full frame, which is why crop sensors are popular for wildlife and sports photography.
How does crop factor affect depth of field and bokeh?
Crop factor reduces apparent depth of field control compared to full frame. To get the same framing and depth of field as a full-frame camera, you need to divide your aperture by the crop factor. A 50mm f/1.8 on a 1.5x crop gives the field of view of 75mm but the depth of field equivalent of roughly f/2.7 on full frame. This means smaller sensors produce deeper depth of field at equivalent framing, making it harder to achieve creamy background bokeh. However, this can be an advantage for landscape and macro photography where maximum sharpness throughout the frame is desired. The actual light-gathering per pixel also differs with sensor size.
Does crop factor change the actual focal length of my lens?
No, crop factor does not physically alter the focal length of your lens. A 50mm lens remains a 50mm lens regardless of the sensor behind it. What changes is the field of view, because a smaller sensor captures only the central portion of the image circle. The equivalent focal length is a way of describing this narrower field of view in terms that full-frame photographers understand. So when we say a 50mm lens on a 1.5x crop has an equivalent focal length of 75mm, we mean it captures the same angular field of view as a 75mm lens would on full frame. The perspective, distortion characteristics, and actual light cone remain those of a 50mm lens.
What are common crop factors for different camera systems?
Full-frame sensors (36x24mm) have a crop factor of 1.0x and are found in cameras like the Sony A7 series, Canon R5, and Nikon Z8. APS-C sensors have a crop factor of approximately 1.5x for Nikon, Sony, and Fuji systems, and 1.6x for Canon APS-C. Micro Four Thirds sensors used by Olympus and Panasonic have a 2.0x crop factor. One-inch sensors common in premium compacts like the Sony RX100 have a 2.7x crop factor. Medium format sensors from Fuji GFX and Hasselblad have crop factors around 0.79x, meaning they are larger than full frame and provide a wider field of view with the same focal length lens.
How does crop factor impact low-light performance and image noise?
Smaller sensors with higher crop factors generally perform worse in low light because each pixel receives less total light, assuming the same megapixel count. The pixel density ratio tells you how many times more densely packed the pixels are compared to full frame. A 1.5x crop sensor with 24 megapixels has the same pixel density as a full-frame sensor with roughly 54 megapixels. Higher pixel density means smaller photosites that capture fewer photons, producing more noise at the same ISO setting. This is why full-frame cameras typically have one to two stops of advantage in noise performance over APS-C sensors, and medium format sensors are even cleaner in challenging lighting situations.
What is crop rotation and why is it important?
Crop rotation means growing different plant families in each bed each year. It prevents soil-borne disease buildup, balances nutrient depletion, and breaks pest cycles. A simple 4-year rotation: legumes (add nitrogen), then leafy greens (use nitrogen), then fruiting crops, then root vegetables. Never follow a crop with the same family.